2015-03-31T20:48:22ZFall detection system for elderly peoplehttp://hdl.handle.net/10198/10552
Título: Fall detection system for elderly people
Autor: Igrejas, G.; Amaral, J.S.; Rodrigues, P.J.
Resumo: accelerometer and a 3-axis gyroscope to measure linear acceleration and angular velocities, respectively.
Information from both sensors is used to characterize movements through selected features extracted from
raw data. A classification system based on a Feedforward Backpropagation Neural Network is then trained,
based on the extracted features. The performed tests present low false positives and low false negatives rates
with good specificity and sensitivity values.2012-01-01T00:00:00ZModeling studies on the synthesis of superabsorbent hydrogels using population balance equationshttp://hdl.handle.net/10198/6607
Título: Modeling studies on the synthesis of superabsorbent hydrogels using population balance equations
Autor: Gonçalves, Miguel; Pinto, Virgínia; Dias, Rolando; Costa, Mário Rui
Resumo: The synthesis of super-absorbent hydrogels is simulated using a kinetic
model based upon population balance equations of generating functions. Dynamics
in a batch reactor of properties such as the weight fraction of gel or average
molecular weights of the soluble fraction can be predicted. This kinetic model
neglects intramolecular cyclization reactions for simplicity (hence predictions can be
valid only for very small amounts of crosslinker) but it can accommodate the
operation with different kinds of crosslinking agents, namely bifunctional (e.g. N,N0-
methylenebisacrylamide), trifunctional (e.g. trimethylolpropane triacrylate) and tetrafunctional
(e.g. tetraallyloxyethane). The influence of the use of such different kinds
of crosslinkers on the dynamics of gelation is discussed. It is also assessed the
impacts of the rate propagation coefficient of the monofunctional monomer
(typically acrylic acid), of the reactivity of the pendant double bonds (PDB) and of
the initial composition on the dynamics of gel production. Some crucial details
concerning the numerical solution of the two-point boundary value problems (TPBVP)
associated with this simulation tool are also presented. Predictions of the proposed
kinetic approach are compared with those obtained using the Theory of the Branching
Processes which is not strictly valid with kinetically controlled polymerization
systems such as those here considered. Important differences between the predictions
of the two approaches are shown. Superabsorbent hydrogels were synthesized
with a 2.5 L batch reactor and the experimental data are used to show that the simple
kinetic model developed is able to capture the main features of this polymerization
system.2011-01-01T00:00:00ZA T-S fuzzy model based on initial FCM partition to estimate the composition of commercial blended vegetable oilshttp://hdl.handle.net/10198/5112
Título: A T-S fuzzy model based on initial FCM partition to estimate the composition of commercial blended vegetable oils
Autor: Igrejas, Getúlio; Amaral, J.S.; Rodrigues, Pedro; Oliveira, M.B.P.P.
Resumo: Several samples of four types of vegetable oils (sunflower, soybean, corn and peanut oils) produced and/or refined in Portugal were analyzed for their fatty acid composition. Data obtained was used to build a fuzzy model to predict the amounts of different vegetable oils (VO) in commercial blends. The strategy used was a combination of a fuzzy clustering method (Fuzzy C-means) and a Takagi-Sugeno fuzzy model. Model was tested with the data from the analysis of simulated blended VO prepared in the laboratory. Results proved the ability of the model in predicting the blend composition. The model was then used to estimate the composition of 21 brands of commercial VO. Most samples have sunflower as the most representative VO in the blend.2010-01-01T00:00:00ZThe use of model samples to estimate the level of fraudulent addition of pork meat in poultry meat by real-time PCRhttp://hdl.handle.net/10198/5065
Título: The use of model samples to estimate the level of fraudulent addition of pork meat in poultry meat by real-time PCR
Autor: Soares, Sónia; Amaral, J.S.; Mafra, I.; Oliveira, M.B.P.P.
Resumo: The undeclared presence of meat species in grounded and comminuted meat products is a concern because it represents an economic fraud, but also for public health, ethical and religious reasons. Meat species identification allows detecting adulterations such as the fraudulent substitution of cheaper meats for more expensive ones. In this work, model samples were prepared at the laboratory containing poultry meat added with known amounts of pork meat. DNA was extracted from the model samples and a real-time polymerase chain reaction (PCR) technique using the SYBR Green I fluorescent dye coupled to melting curve analysis was proposed to obtain a predicting model to estimate the level of possible fraudulent addition of pork meat. The addition of pork meat was detected in the range of 0.1% to 25%, with a high correlation coefficient and PCR efficiency. Calibration curves were obtained with the cycle threshold (Ct) values by using the ΔΔCt method. The application of the approach to blind samples demonstrated the suitability of the proposed methodology for estimating the level of porcine DNA in meat mixtures.2010-01-01T00:00:00Z